Overview:
STAT5 (signal transducers and activators of transcription 5) is a member of the STAT family and this protein is phosphorylated by receptor associated protein kinases in response to cytokines and growth factors (1). The differentiation of T helper (Th) cells is regulated by members of the STAT family of signaling molecules. In BCR-ABL-positive cells, STAT5 is constitutively activated by tyrosine phosphorylation. STAT5 activation results in upregulation of Bcl-XL and increased resistance to induction of apoptosis. STAT5 is involved in expression and growth hormone-mediated sexually dimorphic regulation of cytochrome P450 3A10/lithocholic acid 6 beta-hydroxylase (2).
Gene Aliases:
MGF, STAT5A
Genbank Number:
NM_003152
References:
1.Wang, D. et al: Naturally occurring dominant negative variants of Stat5. Molec. Cell Biol. 16: 6141-6148, 1996.2.A Subramanian et al: STAT 5 and NF-Y are involved in expression and growth hormone-mediated sexually dimorphic regulation of cytochrome P450 3A10/lithocholic acid 6beta-hydroxylase. Nucleic Acids Res. 1998;26(9): 2173–2178.
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所以一个细菌或病毒可以有很多的抗原。
若已进入细胞内。则先由巨噬细胞吞噬降解。并形成抗原-MHC复合体传送到表面。被辅助性T淋巴细胞识别和效应T淋巴细胞识别后。效应T淋巴细胞被激活。分解靶细胞。然后再由效应B细胞分泌的抗体进一步消灭病毒。
还有不清楚的么?
荚膜(capsule)是某些细菌在生长繁殖过程中分泌的一层黏液性物质,包围在细胞壁外,通常这种黏液层厚度小于0.2μm,成分是多糖或多肽,只有在营养丰富时或在动物体内,细菌才产生这种半抗原性质的黏液性物质。它具有保护菌体免受巨噬细胞等的捕捉和吞噬,因而具有抗吞噬抗消化、侵袭力强、与致病性关系密切等特点。像肺炎球菌、炭疽杆菌等都有这类荚膜。有些细菌的荚膜层较薄,小于0.2μm,称为微荚。
像链球菌的M蛋白、伤寒杆菌的Vi抗原、大肠杆菌的K抗原等都属于这类微荚膜。
请赐教!

